Reversing valve assembly

ABSTRACT

A reversing valve for refrigeration and air conditioning systems which is operable to reverse the flow of refrigerant through the heat exchangers which function as the condenser and evaporator in the system. A solenoid plunger assembly is utilized to control the reversing action, and it is mounted on the reversing valve in an arrangement which minimizes heat loss from the coil and which improves the armature action. An arrangement is also provided to assure desired pressure conditions on opposite sides of moving parts so that more effective operation of the valve occurs.

United States Patent Greenawalt 51 Mar. 21, 1972 [54] REVERSING VALVEASSEMBLY [72] Inventor: Fred A. Greenawalt, Fort Lauderdale, Fla.

[73] Assignee: Venture Products Corporation, Fort Lauderdale, Fla.

[22] Filed: Jan. 20, 1970 211 Appl. No.: 4,366

[52] U.S.Cl ..137/106, l37/625.29

[51] Int. Cl. ..G05d 16/10 [58] Field oiSearch ..l37/106, 625.29,625.28; 62/324 [56] References Cited UNITED STATES PATENTS 2,976,7013/1961 Greenawalt ..137/625.29

3,056,574 10/1962 Greenawalt ..137/625.29

3,293,880 12/1966 Greenawalt ..137/625.29

3,400,736 9/1968 Bastle ..l37/625.29 3,527,255 9/1970 Greenawalt..l37/625.29

Primary ExaminerSamuel B. Rothberg Assistant Examiner-William H. WrightAttorney-Olsen and Stephenson [57] ABSTRACT A reversing valve forrefrigeration and air conditioning systems which is operable to reversethe flow of refrigerant through the heat exchangers which function asthe condenser and evaporator in the system. A solenoid plunger assemblyis utilized to control the reversing action, and it is mounted on thereversing valve in an arrangement which minimizes heat loss from thecoil and which improves the armature action. An arrangement is alsoprovided to assure desired pressure conditions on opposite sides ofmoving parts so that more effective operation of the valve occurs.

6 Claims, 6 Drawing Figures PATENTEDHARZI I972 3,650,287

SHEET 2 UF 2 FIG. 4

. INVENTOR 52 FRED A GREENAWALT BY ATTORNEYS REVERSING VALVE ASSEMBLYBACKGROUND OF THE INVENTION The present invention relates to an improvedreversing valve for use in refrigeration and air conditioning systems.

It is known in some refrigeration systems to provide for selectivelyreversing the direction of flow of refrigerant in order to effectperiodic heating of a particular heat exchanger in the system, therebychanging the function of the heat exchanger from an evaporator to acondenser for the purpose of quickly melting frost or ice which may havecollected thereon in the case of a refrigerator, or heating the interiorof a room during cooler periods of weather, in the case of an airconditioner. The term refrigeration systems as used hereinafter, isinclusive of air conditioning systems.

One type of prior art reversing valve of which the present invention isan improvement is disclosed in applicants prior US Pat. No. 3,293,880,issued Dec. 27, 1966. The present invention provides an improvedarrangement of the solenoid assembly so that the solenoid is moreeffectively mounted out of heat transfer relationship with respect tothe refrigerant that flows through the reversing valve. Also, animproved spring arrangement is provided for returning the armature ofthe solenoid to its normal position after the coil is deenergized. Stillother improvements are found in the arrangement for bleedingrefrigerants from the valve passage on opposite ends of the floatingpiston provided therein for reversing the direction of flow in thesystem. Improvements have also been provided whereby the pressures onthe opposite ends of movable parts are more effectively balanced toassure proper movement of such parts.

Accordingly, it is among the objects of the present invention to providean improved reversing valve for refrigeration systems which isconstructed and arranged to minimize heat losses, which provides formore effective balancing of the pressures on opposite sides of movingparts so that such parts can move in the most desirable manner, andwhichhas improved bleeding characteristics within piston chambers to assuremovement of the floating piston in the optimum manner.

According to a preferred form of the present invention, a reversingvalve is provided comprising a valve body having a substantiallystraight passage therein, header means on said body defining the ends ofsaid passage, a pair of fluid inlets in communication with said passageadjacent to the ends thereof, a first port intermediate said ends, apair of second ports located on opposite sides of said first port, apiston slidably supported in said passage for movement between a firstlimitposition adjacent to one end of said passage and a secondlimit-position adjacent to the other end of said passage. The inlets arelocated so that they are in communication with opposite ends of thepiston in both limit-positions, and said piston is shaped so as todefine with the passage a chamber providing communication between thefirst port and one of said second ports when the piston is in its onelimit-position and between the first port and the other of said secondports when the piston is in the other limit-portion. The header means ateach end includes a normally open bleed port each of which is incommunication respectively with one of said second ports and a valvemember for each bleed port responsive to movement of the piston to itsadjacent limit-position to close said bleed port. Supply means areprovided for supplying fluid under pressure to the passage only throughone or the other of said inlets.

The supply means includes a second passage in the body in communicationwith the two inlets at longitudinally spaced intervals of the secondpassage. The body has a fluid inlet port to said second passage betweenthe inlets and a valve element is longitudinally movable therein topositions on opposite sides of said inlet port for selectively directingthe fluid from the inlet port to one or the other of said inlets. Asolenoid assembly is connected to the valve element normally pressingthe valve element to one side of the inlet port and it is operable whenelectrically energized to move the valve element to the other side ofthe inlet port. The solenoid assembly includes a sleeve extending intoone end of the second passage and an armature housed within the sleeveand connected to said valve element. A coil is mounted on the sleevebeyond the end of the second passage so as to be substantially out ofheat transfer relationship with the interior of the second passage. Aspring is operably mounted in the second passage to bias the valveelement to one side of the inlet port. The valve element is dimensionedto provide leakage between its outer periphery and the bore of thesecond passage to provide substantially balanced pressures on oppositesides thereof. Thus, the solenoid assembly is substantially out of heattransfer relationship with respect to the second passage, and the springarrangement and the dimensions of the valve element are such as torequire minimum energy to move the element between its two positions.The relationship of leakage past the valve element and the rate at whichbleeding can occur from the ends of the first passage is such as tominimize the possibility of the floating piston in the first passagebeing obstructed in its movement from one end to the other end when itis desired to reverse the flow of the refrigerant.

Other objects of this invention will appear in the following descriptionand appended claims, reference being had to the accompanying drawingsforming a part of this specification wherein like reference charactersdesignate corresponding parts in the several views.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic illustration of arefrigeration system, showing the reversing valve assembled in thesystem and in a position in which it provides for flow of refrigerant inone direction through the heat exchangers in the system, with thereversing valve in certain parts of the system being shown in sectionfor the purpose of clarity;

FIG. 2 is a schematic illustration similar to FIG. 1, showing thereversing valve in a position for reversing the flow of refrigerantthrough the heat exchangers in the system;

FIG. 3 is an enlarged fragmentary section of one end of the firstpassage in which the floating piston is located, showing details of theheader and bleeder arrangement;

FIG. 4 is a section taken on the lines 4-4 of FIG. 3;

FIG. 5 is an exploded view of one end of the floating piston; and

FIG. 6 is a longitudinal section on the axis of the one end of thefloating piston.

DESCRIPTION OF THE PREFERRED EMBODIMENT Before explaining the presentinvention in detail, it is to be understood that the invention is notlimited in its application to the details of construction andarrangement of parts illustrated in the accompanying drawings, since theinvention is capable of other embodiments and of being practiced orcarried out in various ways. Also, it is to be understood that thephraseology or terminology employed herein is for the purpose ofdescription and not of limitation.

With reference to the drawings, the improved reversing valve of thisinvention, indicated generally at 10, is illustrated in FIG. 1 in arefrigeration system 12 which includes a conventional compressor 14 andheat exchangers 16 and 18, both of which are capable of functioningeither as a condenser or an evaporator. A conventional flow restrictiontube 20 connects the heat exchangers l6 and 18. The compressor 14 hasits discharge connected by a conduit 22 to the inlet port 24 forreversing valve 10. A conduit 26 connects the outlet port 28 forreversing valve 10 with the suction inlet of the compressor 14.

In the illustrated embodiment of the invention, the reversing valve 10includes a valve body 30 having a first passage 31 closed at its ends byheaders 32 and 34 and formed intermediate its ends with the dischargeport 28. A pair of ports 36 and 38 are formed in the valve body 30 onopposite sides of the discharge port 28, with the port 36 beingconnected by a conduit 40 to the heat exchanger 16, and the port 38being connected by a conduit 42 to the heat exchanger 18. Adjacent tothe header 32, the valve body 30 is formed with an inlet 44, andadjacent to the header 34, the valve body 30 is formed with anotherinlet 46.

The valve body 30 has a second passage 48 which is in communication atits opposite ends with the inlets 44 and 46 which are located onopposite sides of the inlet port 24. One end of the passage 48 is closedby the end plate 50, and the other end is closed by the end plate 52. Asolenoid assembly 54 is mounted on one end of the valve body 30 andincludes a sleeve 55 for housing the armature 56. As can be seen in FIG.1, the sleeve 55 extends into the passage 48 into abutment with the oneend plate 52. The armature 56 is connected to a valve element 58, and aspring 60 is operatively positioned between the disk portion 62 and theend plate 52 for normally urging the disk portion to the position shownin FIG. 1. The valve element 58 includes the rod 64 which is affixed tothe disk portion 62 and to the armature 56 so that these parts move as aunit within the passage 48. It will be understood that when the coil ofthe solenoid assembly 54 is energized, the valve element 58 will move tothe position shown in FIG. 2, and when the coil is deenergized, the coilspring 60 will function to move the element 58 to the position shown inFIG. 1. Thus, when the valve element 58 is in the position shown in FIG.1, refrigerant can flow from the inlet port 24 through the secondpassage 48 to the inlet 46 for the first passage 31, and when thesolenoid assembly 54 is energized, and is in the position shown in FIG.2, the refrigerant can flow from the inlet port 24 through the secondpassage 48 to the inlet 44 for the first passage 31.

In the illustrated embodiment of the invention, the disk portion 62 hasa peripheral dimension smaller than that of the bore of the secondpassage 48. so that leakage of refrigerant will occur around theperiphery of the disk portion 62 to maintain the fluid pressure onopposite sides of the disk substantially equal. By minimizing pressuredifferences on opposite sides of the disk portion 62, the most reliableand optimum functioning of the solenoid assembly 54 and its associatedvalve element 58 are assured. It will also be noted that the solenoidassembly 54 is mounted in a position where it is substantially out ofheat transfer relationship to the passage 48 so that when the coil ofthe solenoid assembly 54 is energized, very little heat will betransferred to the refrigerant, thereby assuring optimum efficiency ofthe system.

A free floating piston 66 is slidably supported in the first passage 31.The piston is an integral construction having two axially spacedcylindrical portions 68 and 70, of a diameter to be slidably supportedin the valve body 30, and a reduced diameter stem portion 72 whichconnects the cylinder portions 68 and 70. The cylinder portion 68 isformed with an axially outwardly extending cup-shaped projection 74 andthe cylinder portion 70 is formed with a similar axially outwardlyextending cup-shaped projection 76.

The header 32 which is mounted on one end of the passage 31 has a bleedport 78 centrally located therein and bleed ducts 80 and 82 are providedrespectively in the header 32 and the valve body 40 to discharge intothe port 36. Similarly, the header 34 has a centrally located bleed port84 and ducts 86 and 88 provide communication with the port 38. Alsomounted on the header 32 is a needle valve 90 which is spring biased bythe spring 92 to a normally open position and which can be moved axiallyto close the bleed port 78. As can be seen best in FIGS. 3 and 4, theneedle valve is mounted on the annular ring 94 which is seated andsecured in the end of the header 32 and has a plurality of apertures 96therein to permit flow of fluid from the passage 31 through apertures 96into bleed port 78 and from there through ducts 80 and 82 to the port36.

A similar needle valve 98 is mounted on the header 34 for closing thebleed port 84. In FIG. 1, the needle valve 98 is shown in its closedposition, having been urged to this position by movement of the piston66 to its one limit position. At the same time, the needle valve in theheader 32 is in its open position. Thus, when the coil of the solenoidassembly 54 is deenergized, the flow of the refrigerant will be as isshown by the indicator arrows in FIG. I.

If it is desired to reverse the direction of flow of the refrigerant tofollow the flow circuit shown by the indicator arrows in FIG. 2, thecoil of solenoid assembly 54 will be energized causing the valve element58 to move to the limit-position shown in FIG. 2. This will have theeffect of applying the full pressure of the refrigerant fluid on theright side of the floating piston 66 while at the same timesubstantially reducing fluid pressure from the left side of floatingpiston 66. Initially, needle valve 98 will be in its closed position andneedle valve 90 will be in its open position to assure maximum pressuredifferential on opposite sides of piston 66, and open needle valve 90will allow escape of the fluid trapped on the left side of piston 66 viathe bleed port 78. When the refrigerant fluid has completed movement ofpiston 66 to the position shown in FIG. 2, the flow of refrigerant fluidwill have been reversed through the heat exchangers 16 and 18, asindicated.

The first passage 31 is undercut at the two ports 36 and 38 so that whenthe piston 66 is reversed, it is free floating while passing over theports 36 and 38 to prevent stalling while moving from one limit-positionto the other limit-position. Also, the bleed lines at each header 32 and34 have about six times the capacity as the leakage rate permittedaround the disk portion 62 to provide an ample safety factor when thereversing operation is to be carried out.

To assure that a proper seal is provided between the high and lowpressure sides of the piston 66, a preferred construction is shown inFIGS. 5 and 6. As there shown, the stem portion 72 has secured thereonthe collar 100 against which is seated the cylindrical portion 68.Positioned on the stem portion 72 between the collar 100 and thecylindrical portion 68 is a Teflon seal ring 102, and located within theseal ring 102 is an annular metallic spring 104 which constantly urgesthe seal ring radially outwardly. Thus, the seal ring 102 is constantlyurged into a snug fit with the first passage 31.

It is claimed:

1. In a reversing valve, a valve body having a substantially straightpassage therein, headers on said body defining the ends of said passage,a pair of fluid inlets in communication with said passage adjacent tothe ends thereof, means for supplying fluid under pressure to saidpassage only through one or the other of said inlets, a piston slidablysupported in said passage for movement between a first limit-positionadjacent to one end of said passage and a second limit-position adjacentto the other end of said passage, said inlets being located so that theyare in fluid communication with opposite ends of said piston in bothlimit-positions of said piston, means on each of said headers forming anormally open bleed port and a valve member for each bleed port movablymounted on the header therefor and responsive to movement of said pistonto its adjacent limit-position to close said bleed port, said valvemember extending axially away from said bleed port, and spring meansurging said valve member to an open position, one end of said valvemember being engageable by said piston to urge said valve member to aposition closing said bleed port.

2. In a reserving valve, the combination as is defined in claim 1,wherein said valve body has a first port intermediate the ends thereofand a pair of second ports located on opposite sides of said first port,and said bleed ports being in constant communication respectively withsaid second ports.

3. In a reversing valve, the combination as is defined in claim 2,wherein the inner periphery of said passage is undercut around itscircumference at each of said second ports to provide a free floatingcondition of said end portions when passing over such ports.

4. A reversing valve comprising a valve body having a substantiallystraight passage therein, headers on said body defining the ends of saidpassage, a pair of fluid inlets in communication with said passageadjacent to the ends thereof, a first port intermediate said ends, apair of second ports located on opposite sides of said first ports, apiston slidable supported in said passage for movement between a firstlimit-position adjacent to one end of said passage and a secondlimit-position adjacent to the other end of said passage, said inletsbeing located so that they are in communication with opposite ends ofsaid piston in both limit-positions of said piston, said piston beingshaped so as to define with said passage a chamber providingcommunication between the first port and one of said second ports whenthe piston is in its one limit-position and between the first port andthe other of said second ports when the piston is in its otherlimit-position, each of said headers forming a normally open bleed portin communication with one of said second ports and a valve member foreach bleed port movably mounted on the header therefor and responsive tomovement of said piston to its adjacent limitposition to close saidbleed port, and supply means for supplying fluid under pressure to saidpassage only through one or the other of said inlets, and comprising asecond substantially straight passage in said valve body incommunication with said pair of fluid inlets said body including aninlet port positioned between said inlets, a valve element movablelongitudinally of said passage to opposite sides of said inlet port forselectively directing fluid to one or the other of said inlets andhaving a disk portion with a smaller transverse dimension than thetransverse dimension of said second passage to permit leakage of fluidpast said disk to produce pressure balance on opposite side of saiddisk.

5. A reversing valve as is defined in claim 5, wherein the effectivearea for leakage of fluid past said disk portion is substantially lessthan the effective area for flow of fluid past said disk portion issubstantially less than the effective area for flow of fluid from eachbleed port to its associated second port.

6. In a reversing valve having a body with a first passage, first andsecond inlets to said first passage and a piston in said first passagefor reversing flow of fluid therethrough, supply means for supplyingfluid under pressure to said first passage only through one or the otherof said inlets comprising a second passage in said body in communicationwith said inlets at a longitudinally spaced interval, said body having afluid inlet port to said second passage between said inlets, a valveelement longitudinally movable in said second passage to positions onopposite sides of said inlet port for selectively directing fluid fromsaid inlet port to one or the other of said inlets, and a solenoidassembly connected to said valve element normally biasing said valveelement to one side of said inlet port and operable whenelectrically-energized to move the valve element to the other side ofsaid inlet port, said solenoid assembly including a sleeve extendinginto one end of said second passage, an armature housed within saidsleeve and connected to said valve element, a coil mounted on saidsleeve beyond the end of said second passage, and a spring operablymounted in said second passage to bias said valve element to one side ofsaid inlet port, said valve element being dimensioned to be smaller thanthe bore of said second passage to provide substantially balancedpressures on opposite sides of said valve element.

1. In a reversing valve, a valve body having a substantially straightpassage therein, headers on said body defining the ends of said passage,a pair of fluid inlets in communication with said passage adjacent tothe ends thereof, means for supplying fluid under pressure to saidpassage only through one or the other of said inlets, a piston slidablysupported in said passage for movement between a first limit-positionadjacent to one end of said passage and a second limit-position adjacentto the other end of said passage, said inlets being located so that theyare in fluid communication with opposite ends of said piston in bothlimit-positions of said piston, means on each of said headers forming anormally open bleed port and a valve member for each bleed port movablymounted on the header therefor and responsive to movement of said pistonto its adjacent limit-position to close said bleed port, said valvemember extending axially away from said bleed port, and spring meansurging said valve member to an open position, one end of said valvemember being engageable by said piston to urge said valve member to aposition closing said bleed port.
 2. In a reserving valve, thecombination as is defined in claim 1, wherein said valve body has afirst port intermediate the ends thereof and a pair of second portslocated on opposite sides of said first port, and said bleed ports beingin constant communication respectively with said second ports.
 3. In areversing valve, the combination as is defined in claim 2, wherein theinner periphery of said passage is undercut around its circumference ateach of said second ports to provide a free floating condition of saidend portions when passing over such ports.
 4. A reversing valvecomprising a valve body having a substantially straight passage therein,headers on said body defining the ends of said passage, a pair of fluidinlets in communication with said passage adjacent to the ends thereof,a first port intermediate said ends, a pair of second ports located onopposite sides of said first ports, a piston slidable supported in saidpassage for movement between a first limit-position adjacent to one endof said passage and a second limit-position adjacent to the other end ofsaid passage, said inlets being located so that they are incommunication with opposite ends of said piston in both limit-positionsof said piston, said piston being shaped so as to define with saidpassage a chamber providing communication between the first port and oneof said second ports when the piston is in its one limit-position andbetween the first port and the other of said second ports when thepiston is in its other limit-position, each of said headers forming anormally open bleed port in communication with one of said second portsand a valve member for each bleed port movably mounted on the headertherefor and responsive to movement of said piston to its adjacentlimit-position to close said bleed port, and supply means for supplyingfluid under pressure to said passage only through one or the other ofsaid inlets, and comprising a second substantially straight passage insaid valve body in communication with said pair of fluid inlets saidbody including an inlet port positioned between said inlets, a valveelement movable longitudinally of said passage to opposite sides of saidinlet port for selectively directing fluid to one or the other of saidinlets and having a disk portion with a smaller transverse dimensionthan the transverse dimension of said second passage to permit leakageof fluid past said disk to produce pressure balance on opposite side ofsaid disk.
 5. A reversing valve as is defined in claim 5, wherein theeffective area for leakage of fluid past said disk portion issubstantially less than the effective area for flow of fluid past saiddisk portion is substantially less than the effective area for flow offluid from each bleed port to its associated second port.
 6. In areversing valve having a body with a first passage, first and Secondinlets to said first passage and a piston in said first passage forreversing flow of fluid therethrough, supply means for supplying fluidunder pressure to said first passage only through one or the other ofsaid inlets comprising a second passage in said body in communicationwith said inlets at a longitudinally spaced interval, said body having afluid inlet port to said second passage between said inlets, a valveelement longitudinally movable in said second passage to positions onopposite sides of said inlet port for selectively directing fluid fromsaid inlet port to one or the other of said inlets, and a solenoidassembly connected to said valve element normally biasing said valveelement to one side of said inlet port and operable when electricallyenergized to move the valve element to the other side of said inletport, said solenoid assembly including a sleeve extending into one endof said second passage, an armature housed within said sleeve andconnected to said valve element, a coil mounted on said sleeve beyondthe end of said second passage, and a spring operably mounted in saidsecond passage to bias said valve element to one side of said inletport, said valve element being dimensioned to be smaller than the boreof said second passage to provide substantially balanced pressures onopposite sides of said valve element.